Dentists and their hygienists are faced with an on-going problem of keeping the instruments sharp and properly surfaced with which they clean their patients' teeth. Of course, the primary concern is the comfort and satisfaction of the patient which, obviously, suffers a great deal if the instruments being used are dull and misshapen. In addition, however, the use of dull instruments require more of the operator's time to do a proper job if, in fact, it is even possible to accomplish a satisfactory cleaning with improperly conditioned equipment. Last, but by no means least, is the fact that poorly sharpened and maintained dental instruments become useless more quickly and must be replaced at considerable, but avoidable, expense.
There are basically two techniques used in the sharpening of dental instruments, one a manual method employing a hand-held hone and the other using a mechanical grinder of some sort. Powered grinding wheels have serious limitations which make them highly objectionable to a conscientious technician. To begin with, they remove too much metal and thus contribute to the premature need to dispose of the instrument and buy another. Secondly, the heat developed destroys the temper in the working tip of the instrument. All in all, it is virtually impossible to produce the desired flat even surfaces and sharp edges required in such a instrument using a high speed motor-driven grinding wheel.
Hand-sharpening, too, has its drawbacks. It is slow, tiring and very exacting. The main problem shared by both the manual and motorized techniques is, however, the considerable amount of skill and training required of the operator in order to properly sharpen the wide variety of instrument configurations he or she is called upon to work with.
When the instrument comes from the factory it, obviously, is sharp and properly configured to do the job for which it is intended. Included in addition to the sharp edges are surfaces and surface angles that are very important to the proper functioning of the instrument; however, these surfaces can be obliterated and their reference value lost through just one or two attempts at sharpening the instrument by an unskilled person. For instance, it is quite common to find such instruments with the original planar surfaces rounded to a point where they become all but impossible to reconstruct. Microscopic examination will reveal certain areas to be sharper than others, misshapen contours and excessive metal loss, all of which contribute to the discomfort of the patient, an overly long session in the chair and in all probability a poor cleaning job.